A galvanometer has an internal resistance of 12 $\Omega$ and requires 0.01 A for full scale deflection.To convert it to a voltmeter reading 3 V full scale, one must use a series resistance of:
A)102$\Omega$
B)288 $\Omega$
C)300 $\Omega$
D)360 $\Omega$
E)412 $\Omega$

Question

Quizplus · Accepted Answer

To convert a galvanometer into a voltmeter that reads up to 3 V, the total voltage (V) across the galvanometer and the series resistance (Rs) is given by V = I * (Rg + Rs), where I is the current for full scale deflection (0.01 A) and Rg is the internal resistance of the galvanometer (12 ohms). Rearranging for Rs gives Rs = V/I - Rg = 3/0.01 - 12 = 300 - 12 = 288 ohms.

A Galvanometer Has an Internal Resistance of 12 Ω\OmegaΩ And Requires 0

A Galvanometer Has an Internal Resistance of 12 $\Omega$ And Requires 0